The absorption and emission spectra of HD in the vacuum ultraviolet

The absorption spectrum of HD has been studied under high resolution in the vacuum ultraviolet to 840 A, the emission spectrum to 1000 A. The analysis of the latter gives accurate rotational constants and vibrational intervals of the ground state right up to the dissociation limit. Comparing these experimental data with calculations from ab initio theory, agreement to the same extent as was previously found for H2 and D2 is obtained. Extrapolation of the obs.-calc. values from H2 and D2 to infinite mass yields agreement with the recently revised theoretical values to within less than 0.1 for ν < 7 and less than 0.5 cm-1 for the whole range of observed ν values. (author)